The following relates generally to determining a logic state of a memory cell and more specifically to drift mitigation with embedded refresh.
Memory devices are widely used to store information in various electronic devices such as computers, wireless communication devices, cameras, digital displays, and the like. Information is stored by programming different states of a memory device. For example, binary devices have two states, often denoted by a logic 1 or a logic 0. In other systems, more than two states may be stored. To access the stored information, a component of the electronic device may read, or sense, the stored state in the memory device. To store information, a component of the electronic device may write, or program, the state in the memory device.
Various types of memory devices exist, including magnetic hard disks, random access memory (RAM), read only memory (ROM), dynamic RAM (DRAM), synchronous dynamic RAM (SDRAM), ferroelectric RAM (FeRAM), magnetic RAM (MRAM), resistive RAM (RRAM), flash memory, phase change memory (PCM), and others. Memory devices may be volatile or non-volatile. Non-volatile memory such as PCM may maintain a stored logic state for extended periods of time even in the absence of an external power source. Volatile memory such as DRAM may lose a stored state over time unless it is periodically refreshed by an external power source.
Improving memory devices, generally, may include increasing memory cell density, increasing read/write speeds, increasing reliability, increasing data retention, reducing power consumption, or reducing manufacturing costs, among other metrics. Access operations may cause a shift (e.g., drift) of the threshold voltage of a memory cell. Such a shift may result in reduced reliability relating to subsequent reading the memory cell, and in some instances may result in data loss.